Improvement in bridges



UNITED STATES PATENT UEEICE.

.roi-TN J. arises, or NEwYonir, N. r.

IMPROVEMENT ira-BRIDGES.V

Specification forming part of Letters Patent No. 44,498, dated October 4, 1964.

To @ZZ w/Lom may conccrm.

Be it known that I, JOHN J. ALrses, ofthe city, county, and State of New York, have in- 'portion thereof. Figs. Sand 4 are end views of 'the same.

'Similar letters of reference indicate corresponding parts in the several gures.

This invention relates to a portable bridge, of simple and cheap construction', to be erected or set up in swamps and marshes so as to facilitate the passage of an army, army-wagons,

' the., and permit the' piantingbf batteries in places which have hitherto been considered .unavailable and, in fact, inaccessible.

In order that others skilled in the art to which my invention appertains may be enalled to fully understand and use the same, I will proceed to describe its construction and operation.

In the accompanying drawings, A A represent piles or supports, two pairs of which with their appurtenances form one section ot the bridge. g

To obtain the requisite supporting area at top and adapt the bridge to remain inasteady and iirm condition the piles A are crossed in pairs, as shown in Figs. 3 and 4, thus forming a trestle. 'Ihey are connected at the center by a bolt, a, and these bolts are to be formed eachwith eyes c a', in order that a connectingrod may, it' desired, be employed between the several sections of the bridge to impart longitudinal strength and rigidity thereto.

v In the upper ends of the piles A are slots A', to receive bars or tics B of iron or other suitable material, one bar being employed in connect-ion with each pair of piles, and serving as a coupling and brace at top, for which purpose the said bars and piles are fastened together by pins b.

In the piles A are a series of apertures, a2,

each of which is adapted to receive the pins` I1 and thus admit ot' the vertical'adjustment ofthe bars B for the purpose of bringing all the supporting-points at the same height and making the bridge level wherev the bottom of the swamp is uneven and undulating, as rep-.

resented in Fig. l.

The parts thus far described constitute the main supporting medium, and the piles arev to be prevented from sinking when the bottom of the swamp is soft by having their-lower ends inserted into broad dat sills C; but when the bottom is hard these boards may be dispensed with, and in lieu thereof are employed checkblocks G,shaped somewhat like a boot, one of these blocks being attached to the lower end of each pile A. The check-blocks C will be all sufficient in most places where the bridge is brought into requisition, and while preventing the same from sinking or settling deeper than may be desired they impart lateral support and firmness to the bridge.v

The drawings illustrate two methods of securing in posi-tion the sleepers and roadway D D', upon which the troops, wagons, &c., may pass over the swamp, or which may support a battery. In this latter use great advantage may be derived from the bridge, for the rcason that the guns may be brought to bear upon the enemy from such position that the highl grass and other swamp vegetation will completely conceal the guuners.

One method of securing the sleepers D consists in forming the bars B with strong lianges b b', between which -are inserted the ends of thev sleepers D, the same being secured between the iiangcs by the pins b2. This method is clearly exhibited in Fig. L The other method is represented in Figs. 2 and 8, and consists in placing upon the bar B ,a metallic restplate, E, which is provided with a bracket, c, through which the bar B passes, this bracket serving to prevent the plate from shifting or turning upon the baril. The ends of the sleepers D oi' two respective sections ol' the bridge are fastened to the plate by the pins Z1. rlhe boards D arearrangcd transversely upon the sleepers D, and may be immovably secured in any suitable manner. It' the bridge be cin-v ployed bya retreating army, a number of men may take up the rear sections of the bridge as fast as the troops passover, and thus successful pursuit may be prevented. It' from any cause the bridge should take tire, itis manifest that the reconld be confined' to ver-y sm ill lin is by disconnecting the sections.

Having thus described my invention'vhat I eairn as new therein, and desire t0 seeureby I eters Patent, is-

llie arrangement of the trestles A A, sills C, or cheek-bloeks C', the transverse connecting and supporting bar B, and the longitudi nel sleepers D, the Whole being adapted for The above specification of my improved swamp-bridge Signed this 6th day of Septem-l ber, 1864.

JOHN J. ALISCS. Witnesses:

OCTAVIUS KNIGHT, CHARLES D. SMITH, 

